Cracking of low density polyethylene dissolved in benzene to liquid fuels using zeolite-based catalysts

Researchers proposed numerous solutions to plastic pollution, with the hope to tackle the intractable problems brought by plastic especially to mankind and environment. One of the proposed methods of solving the problem is the conversion of plastic waste to chemicals and fuels through pyrolysis and cracking. However, previous studies focused on polymer cracking in a batch process, which resulted in the wide distribution of the products. Thus, there is a need to develop polymer cracking process in continuous mode and improve the product quality by using a suitable catalyst. The aim of this research is to investigate on catalytic cracking of low density polyethylene (LDPE) in a fixed bed reactor into liquid fuel. LDPE was dissolved in different solvents with similar solubility parameter and the most suitable solvent was selected. The catalytic cracking was then carried out on the LDPE solution using a fixed bed reactor at atmospheric pressure. Parent zeolites and nickel-impregnated zeolites were screened as catalysts for the cracking of LDPE. The change in product composition at different reaction conditions was also studied, and a plausible reaction mechanism was proposed. This was followed by parametric study of the process involving five factors, namely temperature (A), catalyst mass (B), feed flow rate (C), N2 flow rate (D), as well as concentration of LDPE solution (E), and the two responses were LDPE conversion (Y1) and liquid yield (Y2). Two level full factorial design was used to evaluate the factors. It was found that benzene is the most suitable solvent for LDPE dissolution. Catalytic cracking of the LDPE solution produced C1-C8 hydrocarbons in all runs. During the catalyst screening, zeolite Z2 (ZSM-5 zeolite, Si/Al: 1000) was found to be the most promising catalyst, as it was able to obtain high LDPE conversion (99.93%), high liquid yield (92.28%) and low coke formation (0.02%). The parametric analysis showed that four out of five factors (A, B, C and D) produced significant effects on Y1 and Y2. On the other hand, factor E was statistically insignificant on the responses. Analysis on products composition showed that cracking of LDPE over zeolite Z2 produced a high amount of aliphatic branched-chain compounds, together with the moderate amount of cyclic compounds (C7-C12). The reaction conditions also led to alkylation of benzene by the cracking products from LDPE. It is suggested that the catalytic cracking of LDPE is dominated by free radical mechanism, while the influence of carbenium ion mechanism is less pronounced due to low acidity of the catalyst. Hence, it is concluded that catalytic cracking of dissolved LDPE in fixed bed reactor with zeolite Z2 is able to convert LDPE into liquid fuel in gasoline range and has the potential to tackle the plastic pollution

Synthesis of magnetic cellulose as flocculant for PreTreatment of anaerobically treated palm oil mill effluent

Recently, more attentions have been paid to natural polymer-based flocculants in wastewater treatment, since they are believed to be low-cost, nontoxic, and environmentally friendly materials. In present work, a hybrid flocculant namely magnetic cellulose (Magcell) was successfully synthesised through simple crosslinking method. As preliminary study, effect of ratio between magnetite powder and cellulose and also volume of glutaraldehyde as crosslinking agent were selected in this research. Meanwhile, the effectiveness of flocculant was determined by performing a jar test to treat an anaerobically treated palm oil mill effluent (AnPOME). The best ratio cellulose to magnetite powder and volume of closslinker was chose based on optimum removal of turbidity, total suspended solid (TSS), colour and chemical oxygen demand (COD) from sample wastewater. Result shows that the best combination cellulose to magnetite powder are 1: 1 (g/g) with glutaraldehyde volume of 1.5 mL. This optimum parameters show about 74.60 %, 63.90 %, 77.20 %, and 55.80 % reduction in turbidity, colour, TSS, and COD. Overall, approach to produce magnetic cellulose as newly hybrid flocculant has potential to substitute existence flocculants due to the better performance

Construction, characterization, properties and multifunctional applications of stimuli-responsive shape memory polymeric nanoarchitectures:a review

Due to the advent of nanotechnology, deficiencies and limitations inherent in stimuli-responsive shape memory polymeric matrices (SMP), have been effectively mitigated, through the inclusion of a versatile range of organic or inorganic nanoparticulates within the confines of SMP matrice/s. This phenomenon has resulted in the emergence of shape-memory polymeric nanoarchitectures (SMPNs) possessing enhanced and outstanding properties, when compared with the pristine SMP, and this has subsequently enlarged their scope of applications (civil engineering, biomedical gadgets, aerospace, bionics engineering, energy, electronic engineering, household products, and textile engineering). Furthermore, SMPNs enhances athermal stimuli-activities including electroactivity, magneto-activity, water-activity, and photo-activity, as well as shape memory effect (SME) including multiple-shape memory effect (MSME), spatial shape memory effect (SSME), as well as dual-route shape memory effect (DRSME). This elucidation is essential and imperative at this time to enlighten the polymeric universe on new advancements in fabrication, features and applications of stimuli responsive SMPNs. Therefore, this paper, presents, very recently emerging advancements, in construction, characterization, properties and multifunctional applications of stimuli-responsive SMPNs with special emphasis on carbon nanotubes (CNT), carbon nanofibers (CNF), cellulose nanocrystals, and nanoclay reinforced SMPNs.</p

Synthesis and characterization of CaO-TiO2 for transesterification of vegetable palm oil

This study explores the potential of titanium oxide impregnated on calcium oxide (CaO-TiO2) as catalyst in transesterification of vegetable palm oil (VPO) to produce biodiesel. The biodiesel yield increased with catalyst calcination temperature and reaction time, and the usage of CaO-TiO2 led to higher yield of biodiesel production when compared to reaction catalyzed by CaO. Biodiesel yield of 93.33% was recorded when CaO-TiO2 was used at optimized reaction conditions. Catalyst characterizations showed that addition of TiO2 to CaO improved the catalytic property by increasing the surface area and strength of basic sites, hence increased the catalytic performance of CaO-TiO2. This study demonstrates the potential of CaO-TiO2 to convert VPO into biodiesel, and the potential of the catalyst in the conversion of waste cooking oil into renewable fuel

Recent advances of feed-in tariff in Malaysia

In order to promote the growth of renewable energy sector in Malaysia, feed-in tariff (FiT) mechanism has been introduced by Malaysian government in 2011, in accordance with Renewable Energy Act 2011 and Sustainable Energy Development Authority Act 2011. The tariff was enacted to overcome the shortcomings identified in the small renewable energy power (SREP) Program from 2001 to 2010. This paper highlighted some measures adopted to rectify the shortcomings identified during SREP, and the role of Sustainable Energy Development Authority (SEDA) in achieving the above mentioned task. The paper also includes the latest progress on renewable energy projects, especially those related to solar photovoltaic system. It is predicted that solar energy will become the main source of renewable energy in Malaysia by the year 2050

Microplastics and nanoplastics in global food webs: a bibliometric analysis(2009-2019)

This paper presents the research landscape on microplastics and nanoplastics (M/NPs) in global food webs based on a bibliometric analysis of 330 publications published in 2009–2019 extracted from Web of Science. The publications increased tremendously since 2013. Marine Pollution Bulletin is one of the top productive journals for this topic. The publication landscape related to M/NPs in global food webs, as interdisciplinary research, is highly dependent on the funding availability. The high productivities of England, China, USA and European countries are attributed to the funding from the agencies at regional or national levels. Keyword analysis reveals the shift of research hotspots from investigations on M/NPs absorbed by various organisms in the ecosystems to studies on the trophic transfer of M/NPs and sorbed contaminants in the food webs and their associated adverse impacts. Funding agencies play important roles in leading the future development of this topic

Uncovering the dynamics in global carbon dioxide utilization research: a bibliometric analysis (1995-2019)

The anthropogenic emission of carbon dioxide (CO2) into the atmosphere is recognized as the main contributor to global climate change. To date, scientists have developed various strategies, including CO2 utilization technologies, to reduce global carbon emissions. This paper presents the global scientific landscape of the CO2 utilization research from 1995 to 2019 based on a bibliometric analysis of 1875 publications extracted from Web of Science. The findings indicate a major increase in the number of publications and citations received from 2015 to 2019, denoting a fast-emerging research trend. The dynamics of global CO2 utilization research is partly driven by China’s policies and research funding to promote low-carbon economic development. Applied Energy is recognized as a core journal in this research topic. The utilization of CO2 is a multidisciplinary topic that has progressed by multidimensional collaborations at the country and organizations levels, while the formation of co-authorship networks at the individual level is mostly influenced by the authors’ affiliations. Keyword co-occurrence analysis reveals a rapid evolution in the CO2 utilization strategies from chemical fixation in carbonates and epoxides to pilot-scale testing of power-to-gas technologies in Europe and the USA. The development of efficient power-to-fuel technologies and biological utilization routes (using microalgae and bacteria) will probably be the next research priorities in CO2 utilization research

Pyrolysis of low density polyethylene waste in subcritical water optimized by response surface methodology

Pyrolysis of low density polyethylene (LDPE) waste from local waste separation company in subcritical water was conducted to investigate the effect of reaction time, temperature, as well as the mass ratio of water to polymer on the liquid yield. The data obtained from the study were used to optimize the liquid yield using response surface methodology. The range of reaction temperature used was 162-338°C, while the reaction time ranged from 37 min to 143 min, and the ratio of water to polymer ranged from 1.9 to 7.1. It was found that pyrolysis of LDPE waste in subcritical water produced hydrogen, methane, carbon monoxide and carbon dioxide, while the liquid product contained alkanes and alkenes with 10-50 carbons atoms, as well as heptadecanone, dichloroacetic acid and heptadecyl ester. The optimized conditions were 152.3°C, reaction time of 1.2 min and ratio of water solution to polymer of 32.7, with the optimum liquid yield of 13.6 wt% and gases yield of 2.6 wt%

Functional and biological activities of Edible Bird’s Nest (EBN) protein by proteomic and bioinformatic analyses

Edible Bird's Nest (EBN) is a traditional food in Southeast Asia that has been consumed for centuries. In addition to its high protein content, numerous researchers are now exploring the functional proteins of EBN, which have yet to be identified. The present study investigates the EBN proteome by integrating mass spectrometry with protein-based bioinformatics analysis. For protein recovery, three different precipitation techniques were employed; of these, the ammonium sulfate (AS) precipitation technique produced the highest protein yield (74.85%, p &lt; 0.05). The AS precipitation technique was effective in preserving the integrity of EBN proteins as revealed by protein electrophoresis. A total of 35 proteins were identified in the EBN-AS proteins. The predominant function of EBN-AS proteins is immunomodulation, which was further confirmed by their antioxidant [DPPH· activity (23.86%) and ABTS·+ activity (41.97%)], anti-inflammatory [inhibition of nitric oxide production (22.84%), and inhibition of albumin denaturation (19.48%)] assay. Hence, EBN-AS proteins have the potential to regulate the immune system and could be used as natural ingredients for the development of functional foods. Graphical Abstract: (Figure presented.).</p